Introduction
The clinical outcome of spinal cord stimulation (SCS) shows very large individual variation: Some patients experience almost complete pain relief, while others have no beneficial effect at all and ultimately undergo explantation of the SCS device. Therefore, the implanter needs to rely on different assessment tools when evaluating SCS candidates. One such tool is the Pain Catastrophizing Scale (PCS) being a 13-item psychological evaluation instrument used to measure the level of catastrophic thinking in relation to pain. The scale yields a score from 0-52; 0 = no catastrophic thinking, 52 = highest possible level of catastrophic thinking. Previous studies investigating the use of PCS scores as a predictor of SCS outcomes showed conflicting results. The aim of this cohort study was to investigate whether baseline PCS scores in SCS patients could predict: 1) Latest rating on Patients’ Global Impression of Change Scale5 (PGIC) and 2) Risk of undergoing permanent explantation of the SCS device.

Methods
We used data from the Neurizon Neuromodulation Database containing detailed records of patients implanted with a SCS device at either Aarhus, Odense, or Aalborg University Hospitals, Denmark. Patient follow-up was performed approximately every six months and included the PGIC rating, explantations of SCS devices were continuously being registered in the database. Patients were included if they had a baseline PCS score (obtained prior to implantation) and a minimum follow-up of six months. Included patients were grouped by latest PGIC-rating and subsequently by current treatment status (active stimulation /permanently explanted). A one-way ANOVA was used to evaluate the association between baseline PCS scores and latest PGIC rating, while the relation between baseline PCS scores and current treatment status was assessed using an exact T-test.

Results
A total of 249 patients we included: 212 had a follow-up PGIC rating, 41 underwent permanent explantation of their SCS device. Mean baseline PCS score of included patients was 30.4, [29.0, 31.7]. No difference in mean baseline PCS score was found between PGIC groups (p-value = 0.15). Mean baseline PCS scores between groups of treatment status did not differ (Diff = -0.3, [-3.9, 3.3], p-value = 0.87). Follow-up ranged from 0.5 - 8 years (median = 3.0 years) and was not associated with treatment outcomes.

Conclusion
Baseline PCS scores failed to predict both latest PGIC rating and risk of undergoing permanent explantation of the SCS device. Our findings do not provide any support for withholding SCS therapy in patients with a high level of pain catastrophizing.